There are two fundamentally different ways of using DNA to look into the past. One route traces DNA that has come directly from individuals on the maternal and paternal sides.The other sees the world's population as a number of discrete population groups.The first treats people living in past times as individuals making decisions about their own lives while the second interprets the past as a result of collective decisions and tends to use phrases like "wave of settlers" or "mass movement". This is because the statistical methods applied in the second approach are limited to dealing with "populations" and not individuals. They have been developed principally by academics to study large-scale human migration patterns across the world. At Oxford Ancestors we use the first approach, seeing the history of the world as the consequence of individual choices rather than collective action of "populations". The direct lines that we study go back into the past on the maternal and paternal sides and we believe this gives a much more intimate connection with our ancestors than the generalisations of the "population" approach. We connect customers with individual women living thousand of years ago. The "population" approach has some merit in academic research for describing general trends, for instance the spread of agriculture, but it is necessarily fraught with arbitrary or unrealistic assumptions that, when applied to individuals, bear no relationship to reality.